Messages in this thread | | | Date | Tue, 11 Nov 2014 14:28:49 +0000 | From | Daniel Thompson <> | Subject | Re: [PATCH v3.18-rc3] drm: msm: Allow exported dma-bufs to be mapped |
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On 10/11/14 17:36, Rob Clark wrote: > On Mon, Nov 10, 2014 at 12:16 PM, Daniel Thompson > <daniel.thompson@linaro.org> wrote: >> diff --git a/drivers/gpu/drm/msm/msm_gem_prime.c b/drivers/gpu/drm/msm/msm_gem_prime.c >> index ad772fe36115..4e4fa5828d5d 100644 >> --- a/drivers/gpu/drm/msm/msm_gem_prime.c >> +++ b/drivers/gpu/drm/msm/msm_gem_prime.c >> @@ -20,6 +20,14 @@ >> >> #include <linux/dma-buf.h> >> >> +struct dma_buf *msm_gem_prime_export(struct drm_device *dev, >> + struct drm_gem_object *obj, int flags) >> +{ >> + /* we want to be able to write in mmapped buffer */ >> + flags |= O_RDWR; >> + return drm_gem_prime_export(dev, obj, flags); >> +} >> + > > seems like this probably should be done more centrally.. and in fact, > might be better to have something like this in > drm_prime_handle_to_fd_ioctl: > > /* check flags are valid */ > - if (args->flags & ~DRM_CLOEXEC) > + if (args->flags & ~(DRM_CLOEXEC | O_RDWR)) > return -EINVAL; > > so exporter can specify whether to allow mmap or not.
That makes sense I'll try this.
Do we need to wrap O_RDWR in the same way we wrap O_CLOEXEC? (I don't really understand why DRM_CLOEXEC exists; even the patch description from when the symbol was introduced names it O_CLOEXEC).
Also the "flags |= O_RDWR" approach is copied from the sti driver. I'll share a patch to remove it but that will definitely needs Benjamin's ack because it will stop some userspaces working correctly (however I suspect that Benjamin may be the only person currently with such a userspace and that he can be persuaded not to call it a regression).
Daniel.
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